1. Field of the Invention
The present invention relates to a computerized tomography (CT) device using X rays and an image processing method, and, in particular, to a CT image processing technique for extracting a predetermined tissue.
2. Description of the Related Art
It is known that adipose tissues (fat cells) present in a body of a living body (humans and other animals) can be divided into two types, white adipose tissue and brown adipose tissue. White adipose tissue stores energy as a triglyceride and provides energy to the body as prompted. Brown adipose tissue provides a highly advanced thermogenesis or calorigenic action. An increase and an activation of the brown adipose cause reduction in the white adipose which causes adiposis or obesity. Because of this, brown adipose has recently attracted much attention in the medical field. White adipose is present in a large amount in the abdomen, the buttocks, the thighs, the back, the upper arms, regions around internal organs, etc. According to recent research, the brown adipose, on the other hand, is present in a small amount only in specific regions such as, for example, the area behind the neck and that part of the back near the scapula.
Japanese Patent Laid-Open Publication No. 2003-339694 discloses a device which distinguishes between subcutaneous fat and visceral fat based on a CT (computerized tomography) image created through an X-ray measurement. There is, however, no device or method for automatically identifying and extracting images of brown adipose.
In order to quantify the brown adipose on a CT image, a method can be considered in which the brown adipose is manually determined or identified by a user viewing the CT image. With such manual determination, however, the objectivity or reliability of the quantification result of the brown adipose is reduced. In particular, when the brown adipose cannot be clearly distinguished from other tissues on the CT image, the precision of identification is significantly lowered. Moreover, with the manual operation, a large work is required and the process cannot be quickly performed. In particular, when a volume of the brown adipose is to be determined based on a plurality of CT images, these problems become more significant.